> Radials 2:1 Fo 2:1 BW Z VSWR @ Fo
> 0 3340 3522 3920 580 36,0 1.3
> 2 3354 3524 3774 420 45,0 1.0
> 4 3419 3533 3741 322 60,1 1.2
> 8 3445 3550 3742 297 65,4 1.3 (reactance would not go
lower than 4)
>
> The formatting is bad, but in order, left to right:
>
> Number of Radials
> Lower 2:1 vswr point
> Resonant Freq point (Fo)
> Upper 2:1 point
> Bandwidth in kilohertz
> Impedance (R,+/- j) at resonance as shown on the MFJ 269 .
>
> I'm a bit confused by the rising feedpoint impedance with
increased radial
> numbers, yet the narrowing down of the 2:1 swr bandwidth
does indicate
> decreased losses.
You are measuring through a 1/4 wl transmission line
transformer, the 55 foot LMR feedline.
As input impedance at the antenna becomes less, impedance at
the analyzer is higher because of the "Q" section.
All that aside, I would never depend on bandwidth or
impedance as an indicator of efficiency unless you have a
very good feel for how the system behaves. While there are
many cases where it is an indicator, there are also many
cases where the results are counter intuitive and a narrower
SWR BW and lower impedance antenna is less efficient!
73 Tom
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